Thursday, January 8, 2009

I Learned The Coolest Thing On NPR Yesterday

Where was this information when I was in 2nd grade?!?!?!

Yesterday as I was driving home from work, I heard someone describe a shortcut to calculating the 9 times table using his fingers. I would have posted this yesterday but I had to hold auditions first to find just the perfect hand model, LOL.

Let's get started!

OK, you start with all your fingers outstretched and work from left to right - just like you read. For 1 times 9 you would bend your first finger (your little finger on your left hand) to represent one and you are left with 9 fingers (1 x 9 = 9). Now that may not sound impressive but loook below as we do other calculations from the 9 times multiplication table.

Now let's do 9 x 2 which we all know is 18. So, you bend finger #2 (ring finger on left hand because we are going left to right) and see what is left. You have a 1 to the left of the bent finger and 8 to the right. Put them together and you have 18. (Nine times two is 18. )

The next example is 9 x 3. Again starting at left side, bend down finger #3. This leaves 2 on the left of the bent finger and 7 to the right or 27. Three times nine is twenty seven. This is cool, eh?

Bending 4 and leaving 3 and 6 or 36 for nine times four.............

And bending finger #5 leaves 4 and 5 or 45. You can continue this exercise with 6, 7, 8, & 9 and it works everytime. I just may be the last person in the world to learn this but I think it is just the coolest thing!

A round of applause for my Dad's hand modeling performance. {{{clap, clap}}} I believe he may have missed his calling. Ot, who knows, he may have found a second career!


Julie said...

You must have heard this at a different time than I was listening to NPR during the times I was driving in the car all day yesterday too!!! I love NPR. I must remembere to start giving them a donation at the drive times!

Tell your Dad he really was the most perfect hand model!!! That is a neat trick...I had not seen it done like that with your hands in that same manner! Cool!

Love your cube with Daisy on it...I will have to look into that!

Aunt Debbi/kurts mom said...

cute trick

luvonne said...

Your not the last person on the planet to learn this because you just enlightened me (I was physically following along as I read your instructions and following the hand model :) Quite the trick! Where was this information in 2nd or 3rd grade when I could have used it??

My Little Family: said...

Julie it was driving home time, probably between 5:30 - 5:45. Interview was with a guy who wrote a book about something..... I was trying to do this on the steering wheel during stop and go traffic but it wasn't until I stopped in the driveway that I had the "ah-ha" moment. Since then I have been trying to figure out how to use fingers to calculate the others but with no success.

JaMean said...

Wow. Holy cow! You are not the last person in the world to learn this. I have never seen this either!

My 3rd grader is learning times tables at this exact moment, so THANKS! This will most certainly help him! :)

Rusty in Miami said...

I heard the same story and had the same reaction. I think my teachers knew the trick but they didn’t want to share

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